Random Access Violations on shutdown

Environment

• Pythonnet version: 3.0.0.post1
• Python version: 3.8.10
• Operating System: Windows 11
• .NET Runtime: .NET Framework 472

Details

• Describe what you were trying to get done.

  I am getting random access violations during shutdown in pythonnet. The issue can be re-produced with a C# function as simple as

public static int Add(int a, int b) => a + b;

I get the access violation; however, it is not deterministic at all. Some times, it succeeds as expected, other times I get this. Note that I am upgrading from pythonnet 2.5.2 to pythonnet 3.0.0.post1 so this code used to work. All I am doing is invoking this code from python. I am running this python code that uses pythonnet in pytest. I haven't seen this when we were using pythonnet 2.5.2.

• If there was a crash, please include the traceback here.

Unhandled Exception: System.AccessViolationException: Attempted to read or write protected memory. This is often an indication that other memory is corrupt.
   at Python.Runtime.Runtime.PyObject_TYPE(BorrowedReference op)
   at Python.Runtime.Runtime.NullGCHandles(IEnumerable`1 objects)
   at Python.Runtime.Runtime.TryCollectingGarbage(Int32 runs, Boolean forceBreakLoops)
   at Python.Runtime.Runtime.Shutdown()
   at Python.Runtime.PythonEngine.Shutdown()
   at Python.Runtime.Loader.Shutdown(IntPtr data, Int32 size)

Start with the traceback entry points Runtime.NullGCHandles, TryCollectingGarbage, Runtime.Shutdown, PythonEngine.Shutdown, and Loader.Shutdown. Reproduce the shutdown failure in the stated Python 3.8.10, .NET Framework 4.7.2, and Windows 11 environment, then verify that repeated shutdowns no longer produce an access violation.